Armor-plate.



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To all whom it may concern Be it known that I, SAMUEL S. WALES, of Munhall, in the county of Allegheny, State of Pennsylvania, have invented an Improvehighly supercarburized for the purpose of f'by the best Krupp -n'ess.

ndering it more resistant to t e mpa projectiles. While the process of supercarr bonizing improves the surface it is detriniental in-its efl'ect upon the body of the p ate.

'-I have discovered a new composition and a new'process of treatment, by which I am enabled to make armor plate of homogeneous chemical composition without the necessity 'of supercarburizing the surface, and my plate will give much better results in resisting .the impact of projectilesthan have heretofore been obtained. For example, a sixinch plate which I have made according to my invention, has resisted the impact of a hell having. a velocity 15 to 20 per cent. greater than that which could be resisted plates of similar thick- My invention is therefore of great importance, because it enables me to produce anarmor plate having great tenacity and strength, of,'homogeneous composition, and capable of resisting shocks much better than any armor plate whichheretofore has been produced. I

The elements which I alloy with. the iron in order to produce my new steel, are as follows, and in stating them I desire to premise that in addition to these elements,

' those skilled in the art may add other elements if desired, or may vary the PI'OPOI".

to .35 per cent.; nickel, 5 to 12 per cent;

chromium, .15 to .25 per cent; tungsten,

Specification of hetters Patent. Application filed August 1,1 190s. ScIial n). 3,213,659.

Patented Sept. 22, 1914.

.50 to .7 0 per cent. To these elemen s I may add vanadium or molybdenum, from .20 to .50. per cent, or I may substitute vanadium or molybdenum in place of tungsten in W le or in pa The steel which I employ is open hearth steel, and I prefer to add the nickel as a part of the charge of the furnace in a cold condition and to. add the manganese, chro: mium and tungsten in the ladle, or to add them in' the furnace just before tapping, although the time and manner of addition may be varied. The proper proportion of carbon is had by recarburizing in accordance with usual methods. The silicon content of the steel should be as low as possible, say, less than .15 per cent. The sulfur and phosphorus are respectively preferably less than .9 per cent.

The new heat treatment to which I subject the steel is covered in Patent No. 921,925, granted to me on May 18, 1909 for a Method of Treating Armor or Deck Plates, is as follows. Having cast the ingot and forged it. at thekordinary forging temperature, if it is to be' reforged it is subjected to a heat treatment in which it is raised to a temperature of about 700 degrees (1., and cooled slowly, preferably in air. It may then be reforged at the usual reforging temperature, and is then heated to a temperature of about 875 degrees O., which is higher than that to which the plates are reheated in the Krupp process. It is then quenched with water, the duration of the water treatment being preferably about one minute per inch of thickness, the time varying according to the chemical composition of the steel, being preferably somewhatless when the carbon coning will immediately follow the forging; the

plate notbeing allowed to become cold in .the meantime. The steel is then raised to a temperature of about 775 degrees 0., which is also higher than that to which the steel is raised at this period in the Krupp process, and it is then allowed to cool slowly, preferably in air, and may be rough-machined. ,If the plate needs formmg it is then reheated, preferably to about 750 degrees C., at which temperature it may be bent or straightened as desired, therequisite being that the temperature shall be less than that of the "lasttpreceding heat treatment. The plate is then annealed by being heated preferably to about 500 degrees C. by one or more successive, treatments, and is allowed to cool in air. 'It is' then finally machined. The plate is then ready-for the final water hardening, which may be conducted in any suitable way. I prefer, however, to accomplish this Water-hardening by a new method,

in which I heat the entire body of the plate uniformly to a temperature of about 725 to 775 degrees (1, and then quench it with water appliedsimultane'ously on both surfaces so as to harden the plate uniformly throu hout its body. I then soften the plate 0 one surface by heating it on one side only, while the other surface is protected from the heat by loam or otherwise, the temperature being carried preferably to say 500 to 550 degrees C., the effect of which is to soften one surface of the plate, leaving the other side withsubstantiallyits original hardness. On

removing it from the furnace I spray the harder surface of the plate in order to prevent the equalization of'the heat in the body of the plate and its softening throughout.

Those skilled in the art will be able to modify the steps of the heat treatment above I the nickel being present in the proportion of y from 5 to 12 per cent., the chromium in the proportion of from .15 to .25 per cent. and

the tungsten in the proportion of from .50 to .70 per cent.

3. Asteel armor plate containing silicon up to .15 per cent, not more than .35 1per cent. manganese, at least 5 per cent. nic e1, less than .25 per cent. chromium and less than .7 0 per cent. tungsten.

In testimony whereof, I my hand, July 28th, 1906.

SAMUEL s. WALES.

have hereunto set Witnesses:

THOMAS W. BAKENELL, W. R. BALSINGER. 

